Sex, drugs and murder. It’s just another day in the office for Louis Theroux, whose latest documentary series, Dark States, has just aired on BBC Two. Here’s everything you need to know before pressing play…

What’s the premise?

In the three-part series, Theroux visits three different American cities and examines a uniquely devastating human crisis in each – heroin addiction, sex trafficking and murder.

Is the first episode good?

In typical Theroux style, the stories he uncovers are both heartbreaking and fascinating; told in his masterfully tactless way. In this episode, Heroin Town, Theroux visits Huntington, West Virginia, a city where one in four residents is addicted to opiates and one in ten babies is born dependent on drugs. Here, he meets a cast of characters including a young woman called Katillia, whose relationship is exploitative and abusive. We’d recommend a watch, but – be warned – Dark States definitely lives up to its name.

Do critics rate it?

“It’s as if he knows where the invisible string in their backs is, which he pulls to make them talk,” GuardianTV critic Sam Wollaston said of Theroux’s interview subjects. He also called the show “bleak as hell”, because, well, it is. The Telegraph called it “horrifying” and “shocking”, adding that Theroux offered no cure for the tragic situation, leaving viewers to ponder the possible solutions themselves.

Anything else to know?

Twitter users were won over. Many users have said the documentary is so good, Theroux deserves to be knighted. Seriously.

Where to watch it?

Dark States:Heroin Town is available to watch now on BBC iPlayer. The second episode, Trafficking Sex, airs on BBC Two at 9pm on Sunday 15th October and the third episode, Murder in Milwaukee at the same time on Sunday 22nd October.